Real-time Feed-forward Force Compensation for Active Magnetic Bearings System Based on H∞ Controller

There are two kinds of unbalance vibrations—force vibration and displacement vibration due to the existence of unbalance excitation in active magnetic bearings（AMB） system. And two unbalance compensation methods—closed-loop feedback and open loop feed-forward are presented to reduce the force vibration. The transfer function order of the control system directly influencing the system stability will be increased when the closed-loop method is adopted, which makes the real-time compensation not easily achieved. While the open loop method would not increase the primary transfer function order, it provides conditions for real-time compensation. But the real-time compensation signals are not easy to be obtained in the open loop method. To implement real-time force compensation, a new method is proposed to reduce the force vibration caused by the rotor unbalance on the basis of AMB active control. The method realizes real-time and on-line force auto-compensation based on H∞ controller and one novel feed-forward compensation controller, which makes the rotor rotate around its inertia axis. The time-variable feed-forward compensatory signal is provided by a modified adaptive variable step-size least mean square（VSLMS） algorithm. And the relevant least mean square（LMS） algorithm parameters are used to solve the H∞ controller weighting functions. The simulation of the new method to compensate some frequency-variable and sinusoidal signals is completed by MATLAB programming, and real-time compensation is implemented in the actual AMB experimental system. The simulation and experiment results show that the compensation scheme can improve the robust stability and the anti-interference ability of the whole AMB system by using H∞ controller to achieve close-loop control, and then real-time force unbalance compensation is implemented. The proposed research provides a new control strategy containing real-time algorithm and H∞ controller for the force compensation of AMB system. And the stability of the control system is finally improved.

Dynamic Velocity Feed-Forward Compensation Control with RBF-NN System Identification for Industrial Robots

A dynamic velocity feed-forward compensation （RBF-NN） dynamic model identification was presented for control （DVFCC） approach with RBF neural network the adaptive trajectory tracking of industrial robots. The proposed control approach combined the advantages of traditional feedback closed-loop position control and computed torque control based on inverse dynamic model. The feed-forward compensator used a nominal robot dynamics as accurate dynamic model and on-line identification with RBF-NN as uncertain part to improve dynamic modeling accu- racy. The proposed compensation was applied as velocity feed-forward by an inverse velocity controller that can con- vert torque signal into velocity in the standard industrial controller. Then, the need for a torque control interface was avoided in the real-time dynamic control of industrial robot. The simulations and experiments were carried out on a gas cutting manipulator. The results show that the proposed control approach can reduce steady-state error, suppress overshoot and enhance tracking accuracy and efficiency in joint space and Cartesian space, especially under high- speed condition.

Dispersion compensation in an open-loop all-optical chaotic communication system

The optical chaotic communication system using open-loop fiber transmission is studied under strong injection conditions. The optical chaotic communication system with open-loop configuration is studied using fiber transmission under strong injection conditions. The performances of fiber links composed of two types of fiber segments in different dispersion compensation maps are compared by testing the quality of the recovered message with different bit rates and encrypted by chaotic modulation （CM） or chaotic shift keying （CSK）. The result indicates that the performance of the pre-compensation map is always worst. Two types of symmetrical maps are identical whatever the encryption method and bit-rate of message are. For the transmitting and the recovering of message of lower bit rate （1 Gb/s）, the post-compensation map is the best scheme. However, for the message of higher bit rate （2.5 Gb/s）, the parameters in communication system need to be modified properly in order to adapt to the high-speed application. Meanwhile, two types of symmetrical maps are the best scheme. In addition, the CM method is superior to the CSK method for high-speed applications. It is in accordance with the result in a back-to-back configuration system.

ADAPTIVE FEED-FORWARD COMPENSATOR FOR HARMONIC CANCELLATION IN ELECTRO-HYDRAULIC SERVO SYSTEM

Since the dead zone phenomenon occurs in electro-hydraulic servo system, the output of the system corresponding to a sinusoidal input contains higher harmonic besides the fundamental input, which causes harmonic distortion of the output signal. The method for harmonic cancellation based on adaptive filter is proposed. The task is accomplished by generating reference signals with frequency that should be eliminated from the output. The reference inputs are weighted by the adaptive filter in such a way that it closely matches the harmonic. The output of the adaptive filter is a harmonic replica and is injected to the fundamental signal such that the output harmonic is cancelled leaving the desired signal alone, and the total harmonic distortion （THD） is greatly reduced. The weights of filter are adjusted on-line according to the control error by using least-mean-square （LMS） algorithm. Simulation results performed with a hydraulic system demonstrate the efficiency and validity of the proposed adaptive feed-forward compensator （AFC） control scheme

基于高频正交方波注入法的永磁同步电机控制研究

针对传统高频注入法解调过程复杂和观测精度受非理想因素时延影响的不足,提出一种基于高频正交方波注入法的零低速位置估计方法。首先,考虑估计旋转轴系注入的低可靠性,选择将高频信号注入静止轴系,采用简单代数运算提取出高频响应电流,通过解调正向虚拟高频响应电流初步估计转子位置;然后,针对主要非理想因素进行影响分析,在此基础上,通过解调负向虚拟高频响应电流提取出相位滞后角,完成补偿;最后,为避免启动阶段位置收敛错误,通过获取电感变化趋势判断出磁极极性。实验结果表明,所提算法在各类工况均能稳定收敛,且最大平均误差不超过1°,说明了算法的抗扰性以及准确性。

微纳级GaN基VCSEL中周期反射结构与电子阻挡层的设置作用分析

氮化镓(GaN)基微纳米结构生长技术的成熟为微纳级GaN基垂直腔面发射激光器(VCSEL)的制备提供了新的途径。本文设计了基于GaN基轴向异质结微纳米柱的微纳级VCSEL结构,采用Al_(0.8)Ga_(0.2)N/In_(0.2)Ga_(0.8)N应变补偿结构作为上下分布式布拉格反射镜(DBR),其中Al_(0.8)Ga_(0.2)N层的Al组分远高于传统结构中的电子阻挡层(EBL),能够更好地起到电子阻挡的作用。本文使用商用软件PICS3D构建了电子阻挡层处于不同位置的VCSEL数理模型,并进行数值模拟计算,探索和分析物理机理,解释了不同位置EBL对空穴注入效率的影响。结果表明,采用Al_(0.8)Ga_(0.2)N与In_(0.2)Ga_(0.8)N组成的应变补偿DBR可以更好地提高空穴注入效率,优化器件光电性能。

基于预测控制的微滴喷射天线形貌补偿方法

微滴喷射在印刷电子领域有广阔的应用前景,可以在一台设备上完成天线介质基板与导电图案的一体化成形.打印功能器件的表面形貌质量对其电性能有着显著的影响.本文针对微滴喷射三维打印中存在的表面形貌质量难以控制的问题,提出了一种基于预测控制的打印零件形貌补偿方法.首先,基于液滴的逐层堆积行为,建立打印零件形貌预测模型,该模型使用矩阵元素更新描述零件形貌逐层演化,从而准确预测多层打印零件存在的边缘塌陷与表面粗糙度大等形貌缺陷.然后,基于该模型建立预测控制器,通过调整后续层打印图形,实现打印零件形貌缺陷的高效率补偿.采用开环打印与补偿打印的对比实验验证了该方法的有效性.实验结果表明,补偿打印方法使打印零件表面粗糙度下降了66.80%,边缘塌陷量下降了43.22%,有效补偿了打印零件的表面形貌缺陷.最后,采用微滴喷射三维打印工艺制作了微带贴片天线.采用本文提出的补偿打印方法制造的介质基板表面粗糙度低于开环打印样件,从而保证了天线射频层的高质量连接.经测试,其回波损耗参数与方向图更接近仿真结果,从而证明了本研究在印刷电子中的意义.

Rectifier Configurations Based on Harmonic Injecting and Counteracting Principle

On the basis of detailed analysis of a novel harmonic counteracting method which can be used to effectively compensate the supply line harmonic currents of a passive single phase diode bridge rectifier, this paper presents two simpler single phase diode bridge rectifier configurations and their alternatives which can achieve low supply line current THD(total harmonic distortion) too. Moreover, this paper also proposes a few passive hamonic counteracting networks for multi single phase rectifiers which are connected in parallel.

基于电压重注式STATCOM的控制策略研究

随着电力电子器件的制造水平不断提升和人们对电能质量要求越来越高,基于电压重注式变换器的静止同步补偿器(STATCOM)动态响应速度快,不需要滤波装置且输出电压谐波含量较低,并且适用于高压大功率的输电系统。直流电压重注式STATCOM的主电路重注拓扑结构由两个三相全桥串联和附加的重注支路构成,重注支路采用级联H桥结构。重注电压产生过零区间能够实现三相全桥开关零电压通断,设计了重注支路脉冲序列构成方法并提出改进循环逻辑触发时序,仿真表明重注支路在特定的循环触发脉冲作用下可以有效抑制重注式级联H桥中电容电压不平衡。利用仿真平台验证了该变换器在过零关断、消除谐波等工作特性方面的优点。把无功电流作为直接的控制命令,建立闭环控制系统,验证该STATCOM在高压大功率系统中能够有效降低谐波含量和开关频率,提高装置和系统的运行可靠性,特别适用于高压大功率环境。

Proportional-derivative Control of Second-order Tethered Satellites System Based on Extended State Observer and Feed-forward Compensation

This paper researches the proportional-derivative(PD)feedback control with feed-forward compensations from input for a triangular tethered satellite system(TTSS),and the extended state observer(ESO)design which is further incorporated in control to estimate the structural uncertainties in system.By expanding Lagrangian equations under chosen variables,the dynamic equations of TTSS are derived which is the second-order nonlinear equation.Then the feedback control under typical feed-forward compensations is discussed as the nonlinear functions in system are counteracted,and the controlled outputs are computed by deriving the transfer functions of the transformed structures.Moreover,in case of the uncertain structures in system which may constrain the control e®ect,ESO-based PD control is further proposed,and the observed error and controlled accuracy are analyzed by Lyapunov functions.Simulation results on the designed controls are presented to validate the theoretic analyses.

油田注水用自启式管柱蠕动补偿装置研制

油田注水过程中,注水管柱在下入、坐封、注水、停注等工况下切换,会受压力、温度变化的影响,导致其在不同状态下的管柱形变量不同,进而造成管柱频繁蠕动,对锚定器、封隔器等井下工具产生轴向力,影响管柱的长效密封。目前,常用的补偿器为液压启动的方式,下入时因压力激动或封隔器坐封,会出现提前启动的情况。因此,文章研制自启式高温管柱蠕动补偿器,锁定机构采用可溶材料,通过可溶锁块的自溶解特性来启动补偿功能,使其不易受到油管内压力变化的影响,同时采用石墨密封,有效解决了高压动密封问题。

Voltage sag compensation strategy for unified power quality conditioner with simultaneous reactive power injection

Unified power quality conditioner(UPQC)holds the capability of solving power quality problems,especially shows good performance in the voltage sag compensation. In this paper, a compensation strategy based on simultaneous reactive power injection for UPQC(namely UPQC-SRI) is proposed to address the issue of voltage sag. The proposed UPQC-SRI determines the injection angle of compensation voltage with consideration of optimal configuration of UPQC current-carrying.Moreover, the compensation strategy also considers the current-carrying limit of UPQC, and then the zero active power injection region of UPQC-SRI(also called UPQCSRI region) is obtained. Under the conditions which exceed the UPQC-SRI region, the limit value of shunt current is determined by this proposed strategy. Finally, the proposed strategy and the corresponding algorithm are verified under the PSCAD/EMTDC platform. The result indicates the proposed UPQC-SRI strategy in this paper can provide more persistent voltage sag compensation than the previous strategies for the sensitive load.

改进的脉振高频注入永磁同步电动机无传感器控制

针对脉振高频注入法中滤波器相位滞后影响系统动态性能的问题,本文从控制器角度入手,将模型预测控制(MPC)引入速度环替代比例积分(PI)控制,利用其滚动优化和反馈校正的特点提高系统的动态性能,同时对常用的MPC进行改进以获得更好的控制性能。为了获取更好的抗负载扰动能力,采取负载转矩补偿策略,分析传统的q轴参考电流前馈补偿在MPC下存在的问题,提出一种基于q轴参考电压的新补偿法,获得了更好的补偿效果。

考虑交叉耦合效应的混合励磁开关磁链电机转子位置估计

针对使用高频电压注入法估计混合励磁开关磁链永磁(HESFPM)电机转子位置时,由于直轴和交轴之间的交叉耦合效应使得转子位置估计精确度降低的问题,提出了一种对交叉耦合效应进行角度补偿的HESFPM电机励磁绕组高频电压注入位置估计方法。通过电枢绕组α、β轴高频电流响应估计转子位置,分析了交叉耦合效应对所提出的高频电压注入位置估计精确度的影响,通过离线方法测量出该效应导致的交叉饱和角,并进行无位置传感器控制在线角度补偿。最后,通过12槽10极HESFPM样机进行实验验证,实验结果表明电机运行在不同转速、负载工况下,所提方法能够有效减小位置估计直流偏置误差,具有良好动态跟随性能。

高聚物注塑成型工艺过程智能化技术进展

针对聚合物注塑成型高精度、高效率、零缺陷的高性能制造要求,传统工艺参数设定方法和生产过程中存在投产周期、生产成本和质量控制等方面缺乏精准优化的问题,文中综述了当前注塑成型工艺的智能化应对策略和解决方案。针对工艺参数智能设定,从专家系统、案例推理和机器学习三方面总结了当前主流的研究思路;针对过程扰动自适应补偿,从基于机器学期的代理模型和基于在线监测和物理模型两方面简述了当前研究进展,最后对未来注塑产业智能化发展趋势进行了总结。

基于新型高频纹波电流补偿方法的内置式永磁同步电机无传感器控制

高频方波信号注入法已广泛运用于内置式永磁同步电机(IPMSM)无位置传感器低速控制中,该方法可以避免使用滤波器且明显提高系统带宽。然而,在轻载或空载等基波较小时,当逆变器的死区效应使高频电流响应出现畸变,此时逆变器的非线性将会严重影响高频注入法的位置估算精度。针对上述问题,该文重点分析逆变器非线性对IPMSM高频方波注入法的影响,提出一种新型高频纹波电流提取和补偿方法,有效降低死区的影响,提高注入电压的效率,抑制逆变器非线性引起的位置角度误差。通过仿真和实验结果证明,与传统方法相比,该方法可以在注入相同电压幅值的情况下有效降低位置估算误差,验证了所提出方法的可行性和有效性。

基于自适应二阶广义积分器的PMSM无传感器控制

为抑制基于传统高频脉振电压注入算法的永磁同步电机无传感器控制系统中由于滤波器的叠加使用导致的滤波延迟及观测精度较低等问题,提出一种自适应广义二阶积分器(adaptive second-order generalized intergrator, ASOGI),将转速引入特征频率及比例系数中,动态调整系统带宽及选频性能,并将其分别应用于高频响应电流的提取及二倍高频分量滤波,取代带通滤波器(band-pass filter, BPF)和低通滤波器(low-pass filter, LPF),此外,提出一种改进锁相环(phase-locked loop, PLL)算法,基于SOGI提取谐波幅值并消除观测环中注入电压幅频及电机参数的影响。最后运用MATLAB/Simulink进行仿真实验,其中在转速转矩突变时的转速及转矩脉动分别降低了50%和60%,表明了该方法可有效改善系统动态响应及观测精度。

波码无线分层注水工艺高效通讯算法研究

波码分注工艺作为第四代主体分注技术之一,广泛应用于低渗透油田带压作业注水井,具有作业简单、成本低等优势,但存在通信效率低的问题。研究表明导致通信效率低的核心问题是门限压力脉冲过高(0.7 MPa),而影响门限压力脉冲设置过高的原因主要是压力传感器的温度漂移影响和管线噪声干扰。针对现有压力传感器温度漂移和噪声影响,开展了压力传感器的温度补偿算法研究,并提出了一种基于小波变换的自适应滤波算法,采用现场采集的原始压力脉冲数据对提出的理论算法进行了分析,研究结果表明:滤波后压力脉冲噪声峰值从0.3 MPa降低到0.1 MPa,能够满足门限压力脉冲设定从0.5~0.7 MPa降低到0.3 MPa的要求。通过对高效通信算法的研究可以为波码无线分层注水工艺通信效率的提升提供技术理论支撑。

基于BP神经网络的连接器注塑工艺参数多目标优化

为提高连接器注塑工件质量,获得最优的连接器注塑工艺参数,设计一种基于BP神经网络的连接器注塑工艺参数多目标优化方法。利用方差分析法获得对试验结果有显著影响的参数,进而得到更全面的信息。建立相应工艺参数优化模型,并添加多层级的结构;建立BP神经网络集预测模型,映射工艺参数与质量指标的非线性关系,利用预补偿法最终实现工艺参数优化及误差补偿。在相同的测试环境之下,对比于传统优化补偿测试组,新型的优化补偿组所得出的翘曲平均值较低。测试结果证明:新型优化补偿组处理效果更佳,具有一定的应用价值。

基于注入信号法的消弧线圈自动调谐新技术

介绍了传统的消弧线圈自动调整方法。提出采用注入变频信号 ,寻找系统谐振频率 ,测量补偿度、电容电流 ,进行消弧线圈自动跟踪调谐的新方法。测量时无需调整消弧线圈挡位。能适用于老式消弧线圈补偿度的测量。在一个配电网中只需安装一台自动调整消弧线圈 ,就能实现整个配电网的自动调谐 ,无需通信配合。该技术已在现场运行多年 。